Proton radiation hardness and its loss mechanism of Cu2ZnSn(S,Se)4 thin film solar cells

Kesterite Cu2ZnSn(S,Se)4 (CZTSSe) have proven to be promising materials for photovoltaic applications. The current state-of-the-art CZTSSe photovoltaic device improvements in efficiency have been hampered by difficulties in increasing open circuit voltages (VOC). Herein, we thoroughly analyzed the proton irradiation hardness and its loss mechanism of CZTSSe thin film solar cells. The efficiency loss mechanism of the CZTSSe solar cell is proposed by systematically studying the device performance, optical and electrical properties, and distribution changes in elements upon proton irradiation. It was revealed that proton-irradiation-induced element diffusion in device affects the absorber properties and CdS/CZTSSe heterojunction dramatically and deteriorates the performance of the device. Finally, the main factors that may affect device performance of CZTSSe solar cells are highlighted, and the CZTSSe solar cells also demonstrate a remarkable radiation hardness.